It is well known that, as a kind of traditional lamp, the wall lamp has been used in America for over 100 years with the external structure and the installation way unchanged, i.e., the upper and lower covers of the outer radiating shell are mainly assembled through the cooperation between a rotating shaft and a rotating shaft hole. However, it is found that in the actual production process, the way of assembly is not only complicated, but also with higher accuracy on processing the rotating shaft hole and the rotating shaft hole often needs a secondary processing, bringing about low efficiency and high cost.